Scroll compressors with annular sealed high pressure thrust producing member

Abstract

In a scroll compressor enclosed in a casing and a movable scroll member is driven eccentrically by an electric motor, a thrust force created by the compression and applied to the movable scroll member is cancelled by a high pressure chamber which is provided between a surface of the movable scroll member and a frame member and supplied with a pressurized gas delivered from the scroll compressor. The high pressure chamber is formed into an annular shape defined by radially inner and outer tapered walls, and radially inner and outer seal rings having resilience to shrink and expand respectively are provided in the chamber for preventing leakage of the gas out of the high pressure chamber.

What is claimed is: 
     
       1. A scroll compressor including a casing, a frame provided in the casing, a motor and a compressor assembly mounted on opposite sides of said frame, said compressor assembly having a stationary scroll member and a movable scroll member respectively having spiral wraps engaging with each other so that the movable scroll member is driven by said motor eccentrically around the center of a spiroid spiral of said stationary scroll member, said movable scroll member having a planar portion with a lower surface facing said frame, said stationary scroll member having a peripheral portion secured to said frame, said scroll compressor further comprising: an annular member formed adjacent said lower surface and separated therefrom by a gap, said annular surface having radially outer and inner walls and a bottom wall for defining an annular high pressure chamber therebetween, said radially outer and inner walls of said annular member having internal surfaces tapered radially outwardly and inwardly from said bottom wall, respectively;   passage means for supplying a portion of a quantity of compressible fluid delivered from said compressor assembly into said high pressure chamber for reducing a thrust force applied to said movable scroll member;   a radially outer resilient seal ring having at least one part of a radially outer surface thereof tapered to be slidable along said tapered outer wall of said high-pressure chamber; and   a radially inner resilient sealing ring having at least one part of a radially inner surface thereof tapered to be slidable along said tapered inner wall of said high-pressure chamber, said inner and outer sealing rings sealing said annular high-pressure chamber to said lower surface of said planar portion by closing said gap, each of said outer and inner resilient sealing rings including a sealing surface sealingly contacting said lower surface; and   means for maintaining said seal between said annular high-pressure chamber and said lower surface upon a change in the width of said gap, said maintaining means including diameter varying means for resiliently increasing and decreasing the diameters of said inner and outer sealing rings when said sealing rings slide along said respective tapered inner and outer walls.   
     
     
       2. The scroll compressor according to claim 1, wherein said motor is electric. 
     
     
       3. The scroll compressor according to claim 1, wherein said annular member is stationary. 
     
     
       4. The scroll compressor according to claim 1 wherein said annular member is provided separately between said frame and said planar portion of said movable scroll member so as to be secured to said frame and said high pressure chamber is formed in said annular member so as to press said planar portion of said movable scroll member away from said annular member. 
     
     
       5. The scroll compressor according to claim 1, wherein said diameter varying means includes a separated portion formed in each of said seal rings. 
     
     
       6. The scroll compressor according to claim 5, wherein said separated portion comprises a discontinuity in the circumference of each respective seal ring. 
     
     
       7. The scroll compressor according to claim 5 wherein said separate portion is formed between two separate ends of said ring which are slidable with each other circumferentially so as to vary the diameter of the seal ring. 
     
     
       8. The scroll compressor according to claim 7 wherein said two separated ends of said ring are slidable with each other along a circumferential plane which is selected to pass through an intermediate portion of the radial thickness of the seal ring.